This compound is widely used in the development of antibody-drug conjugates (ADCs), where it serves as a key linker component. It facilitates the connection between the antibody and the cytotoxic drug, enabling targeted delivery to specific cells, such as cancer cells. The azido group allows for efficient conjugation through click chemistry, while the Val-Cit sequence is cleavable by cathepsin B, an enzyme often overexpressed in tumor cells. This ensures the drug is released precisely at the target site, minimizing off-target effects. The PEG4 spacer enhances solubility and stability, improving the overall pharmacokinetics of the ADC. Its application is critical in advancing precision medicine for cancer therapy.